Process for truing a diamond wheel utilizing a molybdenum tool

ABSTRACT

A process for truing a resin bonded, diamond grinding wheel utilizing a molybdenum tool as the truing or dressing tool. The molybdenum tool is held in frictional contact with the peripheral work surface of the diamond grinding wheel as it rotates on a spindle, with the molybdenum tool either being stationary, or movable through a predetermined path to form a work surface of particular shape on the periphery of the diamond grinding wheel.

United States Patent r1 1 Kish PROCESS FOR TRUING A DIAMOND WHEELUTILIZING A MOLYBDENUM TOOL [76] Inventor: Istvan T. Kish, l660lExcelsior Blvd.. Minnelonka, Minn. 55343 [22] Filed: Mar. I8, I974 [21]Appl. No.: 452,438

[52] US. 125/11 CD; 5l/283; 5l/293 [51] Int. Cl. B24B 53/06; B24B 53/02[58] Field of Search 5l/262 T, 281 R, 283, 309,

5l/293; 125/11 CD,

[56] References Cited UNITED STATES PATENTS l,590,386 6/1926 Lavallee51/262 T [1|] 3,921,616 1 Nov. 25, 1975 3,078,835 2/l963 Thomas 5l/28l R3.424.566 1/1969 Kuenstle et iII... 51/295 3,528,788 9/l970 Seal i.51/309 Primary ExaminerDonald J. Arnold Allorney. Agent, orFirmWilliamson. Bains & Moore [57] ABSTRACT A process for lruing a resinbonded, diamond grinding wheel utilizing a molybdenum tool as the truingor dressing tool. The molybdenum tool is held in frictional contact withthe peripheral work surface of the 12 Claims, 5 Drawing Figures US.Patent Nov. 25, 1975 FIG, 5

PROCESS FOR TRUING A DIAMOND WHEEL UTILIZING A MOLYBDENUM TOOLBACKGROUND OF THE INVENTION For particular types of finishing andforming operations, diamond grinding wheels are used. For example, resinbonded. diamond grinding wheels are required where close tolerances andextremely smooth finishes are necessary, as in the forming of carbideand tungsten carbide tools. Diamond grinding wheels. like abrasivewheels of any kind. must be trued or dressed from time to time as theywear in order that they may accurately form fine finishes or precisecontour or work pieces, such as tools. Precision grinding utilizingdiamond wheels, as is done in making carbide tools, is becoming less andless popular because it is so difficult to establish and maintain theproper dress on diamond grinding wheels. The silicon carbide andaluminum oxide tools used in the past to dress diamond grinding wheelswear away so rapidly when held in frictional contact with a rotatingdiamond wheel during a dressing operation. that it is extremelydifficult to accurately dress a diamond wheel with such tools. Even ifsufficient material can eventually be removed from a diamond wheel usingsuch tools in a dressing operation, the tremendous wear rate of suchtools against a diamond wheel requires the use of excessive quantitiesof silicon carbide or aluminum oxide tools. Also. the heat and dustgenerated in using silicon carbide or aluminum oxide tools to dressdiamond grinding wheels is highly undesirable.

I have discovered that the aforesaid difficulties can be overcome, andthat the highly effective, accurate and economical dressing of a resinbonded, diamond grinding wheel can be accomplished using a molybdenumtool.

BRIEF SUMMARY OF THE INVENTION The process of this invention fordressing or truing a resin bonded, diamond grinding wheel isparticularly characterized by the use of a molybdenum dressing tool insuch a way that an accurate surface of predetermined shape can be formedon a diamond grinding wheel with the generation of a minimum amount ofheat and dust while wearing away a very minimum amount of the molybdenumtool in comparison with the use ratios of prior tools utilized fordressing diamond wheels.

These basic advantages are achieved by utilizing a molybdenum tool whichis of commercial grade, and preferably having a purity of at least 95percent. The molybdenum tool may take various shapes, such as that of acylinder, disc, bar, or pointed tip, and may be held in a fixed positionor moved through a predetermined path as desired in frictional contactwith the peripheral work surface of a rotating diamond wheel toaccurately form a true work surface of desired contour on the diamondgrinding wheel.

As a particularly beneficial aspect of my improved diamond wheeldressing process, thee molybdenum tool may be used to dress a resinbonded, diamond wheel while the diamond wheel remains mounted on itsnormal work spindle of a grinding machine, the work spindle beingutilized to rotate the diamond wheel during the dressing operation. Thisis in contrast to previously used methods for dressing diamond wheels,in which the high wear ratio of prior dressing materials has requiredthe use of particularly large dressing tools and the mounting of thediamond grinding wheels on special dressing machines permitting accessofthe large dressing tools to the periphery of the diamond wheel.

These and other objects and advantages of my invention will becomereadily apparent as the following description is read in conjunctionwith the accompanying drawings wherein like reference numerals have beenused to designate like elements throughout the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation view insimplified form of a diamond grinding wheel and molybdenum toolpositioned to utilize the truing process of this invention;

FIG. 2 is a side elevation view of the dressing tool and diamond wheelarrangement of FIG. 1;

FIG. 3 is a front elevation view showing an alternative form andarrangement of a molybdenum dressing tool in accordance with myinvention;

FIG. 4 is a side elevation view of the dressing tool and diamond wheelarrangement of FIG. 3: and

FIG. 5 illustrates a variety of grinding wheel shapes which can beformed with the truing process of FIGS. 1 and 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,l have shown in FIGS. 1 and 2 one type of setup for a dressing operationon a grinding wheel utilizing a molybdenum tool. The grinding wheel I isshown mounted on a drive spindle 2 with which it can be rotated at adesired speed in carrying out a truing or dressing operation on thewheel. The grinding wheel will necessarily be a resin bonded. diamondgrinding wheel, since this is the particular type of diamond wheel withwhich a molybdenum tool has proven to be particularly effective in adressing operation. As is well known, such grinding wheels have diamondparticles imbeded and held in a bonding agent in the form of a resin ofsome type. For example, the bonding resin may be Bakelite. Such wheelsare to be distinguished from so-ealled metal bonded diamond wheels withwhich molybdenum tools of my improved dressing process have not beenparticularly effective. Although the spindle 2 on which grinding wheel 1is mounted for the dressing operation may be a rotary spindle on anytype of machine, including that of a special dressing machine, I havefound that my molybdenum tool dressing process may advantageously beutilized to true a resin bonded, diamond grinding wheel while it ismounted on its normal work spindle of a grinding machine. Grindingmachines of various types are well known, and therefore no such machineis illustrated in detail. It will suffice to say that work spindle 2 isrotatably supported on such a machine and is driven by a motor tooperate within a predetermined speed range. The work bed of the grindingmachine is indicated by reference numeral 4.

The peripheral work surface 6 around the circumference of grinding wheel1 is shown with an arcuate shape with a radius formed thereon, forillustrative purposes in FIGS. 1 and 2. As is pointed out below, resinbonded, diamond grinding wheels having contours of variousconfigurations on their peripheral surfaces may be dressed with themolybdenum tool process of this invention. For truing a diamond grindingwheel having such an arcuate peripheral work surface, a bar typemolybdenum tool 8 is preferably utilized. Such an elongated. molybdenumbar formed from molybdenum bar stock of commercial grade and quality hasbeen successfully used to dress a resin bonded. diamond grinding wheel.Although such commercial quality molybdenum would normally be over 99percent pure. a molybdenum tool. in whatever form utilized in mydressing process. would provide satisfactory results if it were of atleast 95 percent pure molybdenum. In the dressing setup shown in FIGS. Iand 2, molybdenum bar tool 8 is held in a dressing fixture 10 which maybe advantageously secured in place on the work bed 40f the grindingmachine on which diamond wheel I is mounted for normal grindingoperations. Tool support fixture 10 has a rotary head 12 with an uprightmember I4 affixed thereto for rotation about the rotary axis 15 of head12. Projecting forwardly from upright member 14 at substantially rightangles thereto is a tool mounting arm 16 apertured at its outer end toreceive a tool holding sleeve 18. Molybdenum tool bar 8 is removablysecured within sleeve 18 in the upright position shown in FIGS. I and 2.Tool bar 8 is so mounted that its outer, flat tip portion 20 is incontact with the peripheral work surface 6 of diamond grinding wheel I.

A dressing operation is carried out on grinding wheel I using theaforesaid setup. by rotating grinding wheel 1 at a predetermined speedwith work spindle 2. Simultaneously. as wheel I is rotating. rotary headI2 of the tool fixture is rotated about axis 15 in a reciprocatingfashion as indicated by the directional arrow in FIG. I. to thereby movethe work tip 20 of molybdenum tool bar 8 back and forth in an arcuatepath over the circumferential. peripheral edge surface 6 of grindingwheel I as it rotates. Tool bar 8 is moved generally transversely of theperipheral work surface 6 of grinding wheel I in a vertical plane whichwill normally be oriented at right angles with respect to the plane ofgrinding wheel 1. The arcuate movement of molybdenum tool bar 8 over theentire peripheral work surface 6 of grinding wheel I is illustrated inFIG. I by showing tool bar Bin phantom lines in one of the positions itwill assume during the truing operation.

By moving molybdenum tool bar 8 back and forth through an arcuate pathwith its tip 20 in frictional contact with the peripheral work surface 6of wheel I as it rotates. tool bar 8 will form a precise radius on theperipheral work surface 6 of wheel I to thereby provide the exactarcuate contour of predetermined radius required on peripheral worksurface 6. It is to be noted that with the dressing setup shown in FIGS.1 and 2, the rotational axis 22 of grinding wheel 1 extendssubstantially perpendicular to the plane of wheel 1. For forming apredetermined radius on the peripheral work surface 6 of wheel I.molybdenum tool bar 8 is preferably mounted as shown in FIGS. 1 and 2with its elongated support arm 16 extending at right angles torotational axis 22 of grinding wheel 1. Those skilled in the art willappreciate that tool bar 8 could be held stationary, or moved throughvarious types of predetermined paths in order to true a flat or arcuatesurface of particular contour on the peripheral work surface of adiamond grinding wheel. In FIG. 5 I have illustrated in cross section anumber of radius and angled surfaces which can accurately be formed on aresin bonded, diamond grinding wheel using a molybdenum tool bar 8mounted on a radius-angle dresser secured in place on a work bed 4 of agrinding machine so as to hold the molybdenum tool bar in properposition with respect to 4 the peripheral work surface of the grindingwheel I. It will be appreciated that the dressing setup illustrated inFIGS. I and 2 is primarily intended for generating convex forms. such asradii and angles. singly or in combinations as illustrated in FIG. 5. onthe peripheral work surface of the grinding wheel.

In FIGS. 3 and 4 I have shown an alternative setup for a dressingoperation utilizing a molybdenum tool 24 of cylindrical shape. Tool 24is mounted on the forward end 2611 of a drive spindle 26 rotatablysupported on a fixture 28. Drive spindle 26 is supported for rotationalmovement abouts its longitudinal axis 30. and is driven by a motor notshown. as is rotary head 12 of tool support fixture I0 shown in FIGS. Iand 2. As is the case with respect to the dressing tool setup of FIGS. 1and 2, dressing tool mounting FIG. 28 is directly supported on the workbed 32 ofa grinding machine of conventional design. Drive spindle 26 isso positioned that molybdenum tool cylinder 24 will be positioned asshown with its cylindrical peripheral surface in tangential line contactwith the circular peripheral work surface 34 of a diamond grinding wheel36. Wheel 36 would also be a resin bonded. diamond grinding wheel of thetype with which the molbdenum truing tools of this invention have provento be particularly efficient and effective. Diamond grinding wheel 36 isshown mounted on a spindle 38 for rotation with the spindle about itslongitudinal axis 40. Although a special work spindle on a dressingmachine could be utilized to support and rotate grinding wheel 36 duringa truing operation. spindle 38 will preferably be the normal workspindle of a grinding machine on which diamond wheel 36 is normallymounted for grinding operations. Tool support fixture 28 is supported onthe work bed 32 of the grinding machine at a position such that dressingtool 24 will be positioned as shown in frictional contact with theperipheral surface 34 of wheel 36.

With work spindle 38 driving diamond grinding wheel 36 at apredetermined speed. molybdenum tool cylinder is simultaneously rotatedin frictional contact with the peripheral work surface 34 of wheel 36.The rotational axis 30 for cylindrical molybdenum tool 24 is disposedsubstantially at right angles to the rotational axis 40 of grindingwheel work spindle 38. Thus, with molybdenum tool 24 being a rightcylinder. as shown, it will true and form a substantially flat orstraight surface on the circular periphery 34 of diamond grinding wheel36. In order to form an accurate. flat work surface over the entireperiphery 34 of diamond grinding wheel 36, molybdenum tool cylinder 24may be reciprocated horizontally in a direction parallel to therotational axis 40 of wheel 36, as is indicated by the directionalarrows in FIG. 3. This may readily be accomplished by reciprocating thework bed 32 of the grinding machine on which tool fixture 28 is mounted.such work beds of grinding machines normally being reciprocal in ahorizontal plane for the purpose of moving a work piece back and forthunder a diamond grinding wheel during a finishing operation.

Although the dressing setup of FIGS. 3 and 4 shows an elongated.cylindrical molybdenum tool I contemplate that a disc-type cylindricalsegment of shorter length could also be used in such a setup. Theelongated cylindrical tool 24 shown in FIGS. 3 and 4 has the advantagethat it presents a substantial lenth of tool surface to the peripheralsurface 34 of grinding wheel 36, and therefore will not wear away asquickly as would a thin, disc-like dressing tool. Also, in addition tothe bar and cylinder type molybdenum dressing tools disclosed in FIGS. 1through 4, l contemplate that other types and shapes of molybdenum toolscould be used satisfactorily in dressing a resin bonded. diamondgrinding wheel. For example, the tool could be a bar or rod with apointed tip. or possibly even a flat plate against which the peripheralsurface of a diamond grinding wheel would rotate during a truingoperation.

1 have found that particularly accurate dresing of resin bonded. diamondgrinding wheels with a minimum of wear of the dressing tool can beaccomplished utilizing a cold rolled molybdenum tool. The reason forimproved performance with such a cold rolled molybdenum tool is notprecisely known. However, different metallurgical properties, includinggrain dispersion and hardness are apparently achieved in a cold rolledmolybdenum tool, in contrast to a hot worked molybdenum tool, which mayaccount for the improved results when such a tool is used to dress aresin bonded, diamond wheel.

One of the most important advantages achieved by the use of a molybdenumtool as disclosed herein for dressing or truing a resin bonded, diamondgrinding wheel is the low wear ratio of the tool with respect to thegrinding wheel. Silicon carbide and aluminum oxide tools which havetraditionally been used for dressing diamond grinding wheels of bothresin bonded, and metal bonded types, have had wear ratios of as high aslOO to I. That is to say, 100 times as much of such dressing tools wearsaway during a dressing operation, as does the resin bonded, diamondwheel. Molybdenum dressing tools used in truing operations as disclosedherein have shown a very minimal wear ratio of the tool to the grindingwheel of only about 2 to 1. This small amount of wear of the molybdenumtool in comparison with that of higher tools utilized for dressing resinbonded, diamond wheels, also explains to a large degree the minimumamount of dust and heat generated during a truing operation utilizing amoybdenum tool. Silicon carbide tools, for example, wear away so rapidlywhen used for dressing a diamond grinding wheel. that a tremendousamount of dust and heat is generated. This is highly undesirable forobvious reasons, and special vacuum pickup devices must be utilized toremove the dust during the dressing operation. Utilizing a molybdenumdressing tool on a resin bonded, diamond grinding wheel, I have foundthat the temperatures generated are so low that either the grindingwheel or the molybdenum dressing tool can safely be touched by handimmediately after a truing operation has been completed. Neither thegrinding wheel itself, or the molybdenum tool reach a temperature inexcess of 200 F during a truing operation.

One of the significant problems directly related to the hightemperatures generated in dressing diamond wheels with aluminum oxide orsilicon carbide tools is burning and glazing of the peripheral surfaceof the resin bonded, diamond wheels during the truing operation. Thehigh temperatures encountered with such tools cause the resin bondingelements to melt and glaze over and around the diamond particles on theperiphery of the grinding wheel. As a result, a final dressing operationutilizing a separate abrasive is frequently required to open up theperipheral surface of a resin bonded, diamond grinding wheel to exposethe tips of diamond particles after a truing operation utilizing asilicon carbide or aluminum oxide tool. The molybdenum truing tool ofthis invention produces a more open face initially on the peripheralsurface of a resin bonded, diamond wheel with good exposure of diamondparticles. There is no need for a final. additional dressing operationutilizing a special abrasive after the molybdenum tool truing process.since the temperatures generated in the use of a molybdenum tool againsta resin bonded diamond wheel are not high enough to melt and glazc theresin bonding material. The high temperatures, glazing of the bondingagents. and high wear ratios with resulting dust generation, make itvery difficult to obtain the necessary accurate contours on diamondwheels required for precision grinding operations utilizing such wheels.As a result. much more accurate. finer finishes can be achieved on workpieces, and particularly on carbide and tungsten carbide tools, using amolybdenum dressed. resin bonded diamond wheel. For example, I have beenable to achieve finishes with tolerances as close as 2 micro inches witha resin bonded. diamond grinding wheel dressed with a molybdenum tool.This is in contrast to the finishes of IS to 20 micro inches achievablein the past with conventionally dressed resin bonded. diamond wheels.

Another particularly significant benefit realized from the use ofmolybdenum dressing tools to true resin bonded, diamond grinding wheelsis that the truing operation can be carried out with the diamondgrinding wheel mounted on its work spindle of a grinding machine. Thetremendously high wear rate of silicon carbide and aluminum oxide toolsused in the past to dress diamond grinding wheels has required the useof particularly large tools in the nature of bars or cylinders of suchdressing materials. Such dressing tools are so large, that they cannotbe mounted in a fixture and positioned in working relation to a grindingwheel with the grinding wheelmounted on its work spindle on an ordinarygrinding machine. Traditionally. the grinding wheel has been removedfrom its work spindle and mounted on the spindle of a special dressingmachine utilizing a relatively large aluminum oxide or silicon carbidetool, such as a very large diameter silicon carbide disc or cylinder.Because of the extremely high wear rate of such prior dressingmaterials, it is simply impractical to attempt to use the small tools inthe nature of small discs or bars. which will be required to achieveaccess to the periphery of a diamond grinding wheel mounted on itsnormal work spindle. Such small tools as those illustrated in FIGS. 1through 4 in the nature of tool bars or cylinders not over severalinches long or several inches in diameter would simply wear away soquickly if made from silicon carbide or aluminum oxide and used to dressa diamond wheel, that the tools would have to be replaced repeatedlywithout actually removing any significant amount of material from theperiphery of the diamond wheel. The minimum wear ratio of tool todiamond wheel on the order of 2 to I achieved with my molybdenum toolsovercomes these problems, and permits a very small molybdenum tool to beused to dress a resin bonded diamond grinding wheel with the wheelmounted on its normal work spindle. Thus. the grinding wheel does nothave to be removed from its machine and placed on a special drivespindle of a truing machine to carry out a truing operation. As will beappreciated by those skilled in the art, this necessarily improves theaccuracy which can be achieved in the form dressing of a diamondgrinding wheel utilizing a molybdenum tool with the grinding wheelmounted on its work spindle. If the grinding wheel has to be transferredfrom one spindle to another in the course of a truing operation.accuracy in the truing operation will necessarily be lost because ofunavoidable differences in tolerances between the work spindle of agrinding machine and the special drive spindle of a dressing machine onwhich the wheel would be mounted during a dressing operation. The relatively low wear ratio of a molybdenum tool with respect to a resinbonded. diamond wheel permits a rela tively small molybdenum tool suchas those shown in FIGS. 1 through 4 to accomplish the dressing operationwith the diamond wheel rotating on its normal work spindle of a grindingmachine. A small molybdenum tool can readily be mounted in conventionalradiusangle dressing devices such as those shown in FIGS. 1 through 4,and positioned in working relation to the peripheral surface of agrinding wheel with the tool dressing fixture mounted on the work bed ofthe grinding machine. As noted above, it would be impossible to achieveaccess to the peripheral surface of a grinding wheel mounted on itsnormal work spindle if a large tool had to be used in the dressingoperation. as is the case with previously utilized silicon carbide andaluminum oxide tools.

When a dressing operation is carried out in the preferred manner withthe grinding wheel mounted on its work spindle. the wheel will berotated during the dressing operation within a predetermined speed rangeavailable on the grinding machine. Normally. the speed rangeavailability on conventional grinding machines is between 5000 and 5500surface feet per minute. Satisfactory truing results have been achievedusing a mo lybdenum tool held in frictional contact with the worksurface of a grinding wheel rotating within such a speed range. However,improved results in the form of particularly accurate finishes andminimum wear of the molybdenum tool have been achieved with the grindingwheel operating at slower speeds within a range of from 600 to 700surface feet per minute. Such lower speed ranges for the grinding wheelwork spindle are available only on certain types of grinding machinesutilized for special forming operations.

The easier. less expensive and more accurate truing of resin bonded.diamond grinding wheels possible with the use of molybdenum tools asdescribed herein with the grinding wheel mounted on its normal workspindle. will make the forming ofcarbide and tungsten carbide tools bymeans of diamond grinding wheels much more feasible and attractive totool makers. Presently. machinists avoid making carbide tools because itis so difficult to maintain and control the proper dress on diamondgrinding wheels required for the finishing of carbide tools and workpieces of any kind. This is considered to be a significant benefit.since carbide tools wear so much better and last so much longer thansteel tools.

Although I have described my improved dressing process for resin bonded,diamond wheels with respect to particular molybdenum tools and toolsetups, l anticipate that various changes may be made in the size,shape, and arrangement of molybdenum dressing tools without departingfrom the spirit and scope of this invention as defined by the followingclaims:

What is claimed is:

l. A process for truing a resin bonded, diamond grinding wheelcomprising:

8 rotating a resin bonded. diamond grinding wheel about a rotationalaxis extending sn -t.tnt:ally normal to the plane of the wheel; andsimultaneously holding a molybdenum tool in frictional contact with theperipheral work surface of said grinding wheel while it rotates. 2. Adiamond grinding wheel truing process as do fined in claim 1 wherein:

said molybdenum tool is commercial quality molybdenum of at leastpercent purity. 3. A diamond grinding wheel truing process as de finedin claim 1 wherein:

said molybdenum tool is cold rolled molybdenum. 4. A diamond grindingwheel truing process as defined in claim 1 wherein:

said diamond grinding wheel is mounted on its normal work spindle of agrinding machine during said truing operation. with said molybdenum toolbeing moved into frictional contact with the peripheral work surface ofsaid grinding wheel as it rotates on its work spindle; and moving saidmolybdenum tool back and forth through an arcuate path over thecircumferential. peripheral edge surface of said grinding wheeltransversely of said edge surface in a plane angularly oriented withrespect to the plane of said grinding wheel as said grinding wheelrotates on said work spindle. thereby forming an arcuate peripheral worksurface around the circumference of said grinding wheel. 5. A diamondgrinding wheel truing process as defined in claim 4 wherein:

said molybdenum tool is in the form of a bar having a tip held incontact with the peripheral edge surface of said grinding wheel as saidbar is moved back and forth through said arcuate path with said grindingwheel rotating on its work spindle. 6. A process for truing a resinbonded. diamond grinding wheel comprising:

rotating a resin bonded. diamond grinding wheel with a work spindle of agrinding machine on which said diamond grinding wheel is normallymounted for grinding operations; and simultaneously holding a molybdenumdressing tool in frictional engagement with the circumferential,peripheral work surface of the grinding wheel while it is rotating. 7. Adiamond grinding wheel truing process as defined in claim 6 wherein:

said diamond grinding wheel is rotated at a speed of between 600 and 700surface feet per minute dur ing said truing process. 8. A diamondgrinding wheel truing process as defined in claim 6 wherein:

said molybdenum tool is in the form of a cylindrical member which isrotated about its longitudinal axis during said truing process with itscylindrical peripheral surface in tangential line contact with thecircular peripheral work surface of said grinding wheel as it rotates.

9. A diamond grinding wheel truing process as defined in claim 8wherein:

said cylindrical. molybdenum tool is mounted for rotational movement ona spindle having its longitudinal. rotational axis disposedsubstantially at right angles to the rotational axis of said grindingwheel work spindle.

10. A diamond grinding wheel truing process as de- A diamond grindingwheel "Hing P 115 fined in claim 6 wherein: fined in Claim 9 wherein:

u said cylindricaL molybdenum tool is moved back and molybdenum movedback and forth forthin atraversing stroke across the entire periphlhmugharcuate P over the circular P 5 eral width of the grinding wheel in adirection pareral surface of said grinding wheel transversely of allelto the rotational axis of the grinding wheel as said surface in a planeangularly oriented with rell FORRES- l2. A diamond grinding wheel truingprocess as defined in claim 6 wherein:

, w said diamond grinding wheel is rotated at a speed of thereby formmgan inmate penpheral work between 5000 and 5500 surface feet per minuteface on the circular periphery of said grinding during id truing pumawheel.

spect to the plane of said grinding wheel as said grinding wheel rotateson said work spindle.

1. A PROCESS FOR TRUING A RESIN BONDED, DIAMOND GRINDING WHEEL COMPRISING: ROTATING A RESIN BONDED, DIAMOND GRINDING WHEEL ABOUT A ROTATIONAL AXIS EXTENDING SUBSTANTIALLY NORMAL TO THE PLANE OF THE WHEEL; AND SIMULTANEOUSLY HOLDING A MOLYBDENUM TOOL IN FRICTIONAL CONTACT WITH THE PERIPHERAL WORK SURFACE OF SAID GRINDING WHEEL WHILE IT ROTATES.
 2. A diamond grinding wheel truing process as defined in claim 1 wherein: said molybdenum tool is commercial quality molybdenum of at least 95 percent purity.
 3. A diamond grinding wheel truing process as defined in claim 1 wherein: said molybdenum tool is cold rolled molybdenum.
 4. A diamond grinding wheel truing process as defined in claim 1 wherein: said diamond grinding wheel is mounted on its normal work spindle of a grinding machine during said truing operation, with said molybdenum tool being moved into frictional contact with the peripheral work surface of said grinding wheel as it rotates on its work spindle; and moving said molybdenum tool back and forth through an arcuate path over the circumferential, peripheral edge surface of said grinding wheel transversely of said edge surface in a plane angularly oriented with respect to the plane of said grinding wheel as said grinding wheel rotates on said work spindle, thereby forming an arcuate peripheral work surface around the circumference of said grinding wheel.
 5. A diamond grinding wheel truing process as defined in claim 4 wherein: said molybdenum tool is in the form of a bar having a tip held in contact with the peripheral edge surface of said grinding wheel as said bar is moved back and forth through said arcuate path with said grinding wheel rotating on its work spindle.
 6. A process for truing a resin bonded, diamond grinding wheel comprising: rotating a resin bonded, diamond grinding wheel with a work spindle of a grinding machine on which said diamond grinding wheel is normally mounted for grinding operations; and simultaneously holding a molybdenum dressing tool in frictional engagement with the circumferential, peripheral work surface of the grinding wheel while it is rotating.
 7. A diamond grinding wheel truing process as defined in claim 6 wherein: said diamond grinding wheel is rotated at a speed of between 600 and 700 surface feet per minute during said truing process.
 8. A diamond grinding wheel truing process as defined in claim 6 wherein: said molybdenum tool is in the form of a cylindrical member which is rotated about its longitudinal axis during said truing process with its cylindrical peripheral surface in tangential line contact with the circular peripheral work surface of said grinding wheel as it rotates.
 9. A diamond grinding wheel truing process as defined in claim 8 wherein: said cylindrical, molybdenum tool is mounted for rotational movement on a spindle having its longitudinal, rotational axis disposed substantially at right angles to the rotational axis of said grinding wheel work spindle.
 10. A diamond grinding wheel truing process as defined in claim 6 wherein: said molybdenum tool is moved back and forth through an arcuate path over the circular, peripheral surface of said grinding wheel transversely of said surface in a plane angularly oriented with respect to the plane of said grinding wheel as said grinding wheel rotates on said work spindle, thereby forming an arcuate, peripheral work surface on the circular periphery of said grinding wheel.
 11. A diamond grinding wheel truing process as defined in claim 9 wherein: said cylindrical, molybdenum tool is moved back and forth in a traversing stroke across the entire peripheral width of the grinding wheel in a direction parallel to the rotational axis of the grinding wheel as it rotates.
 12. A diamond grinding wheel truing process as defined in claim 6 wherein: said diamond grinding wheel is rotated at a speed of between 5000 and 5500 surface feet per minute during said truing process. 